I idle at low 20's with one core, third one I think, at 15 to 18c according to realtemp. Onstock clocks I've gotten it as low as 10c. I would of quoted you but im on my phone sorry.
No worries broski. Just glad to see that uneven core temps aren't necessarily unusual. Two of my cores hover around 10-15 degrees cooler than the main and secondary. --- i5 3570k @4.2 GHz/ Asrock Z77 Extreme4 / 8GB G.Skill Sniper 1866 / MSI GTX 560 / Corsair Force GT 120GB / Seagate Barracuda 2TB